I have the 11 speaker setup, to start with I thought one of the subs was blown, but mainly the farting noise of the stock subs comes from the surrounding trim (at least on my car it did)...

As I couldn't really find any concrete documents on the wattage and resistance of the subs (which I know at least are 2 ohm and probably 30-40watts RMS) I felt it best just to have a go at applying some good old Dynamat to try and resolve the problem..... and it seems to have worked quite well, more punch to the subs and less farty noise.... almost no farty noise in fact..... not bad for an afternoons work... as I couldn't find a guide, here's how:

Wind deflector off, prise off the little caps to reveal some screws, pop those out...

Prise apart the rollbar cover...

Unscrew.....

Pull out the weather trim...

Pull up to remove the kick plate guard, you'll need to remove the rivets and slide them back in to put it back on later...

You need to unscrew and remove the speaker before doing this part, and make sure you have a small precision flat head to remove the wire connections for the rear courtesy light and the speaker - remember extra care must be taken when using screw drivers near speakers...

Wasn't 100% sure whether these rivets should be removed but I wiggled this around until it came free

Remove cheeky bolt (you need to remove the trim nearer to the front of the car to reveal this)

Pop this off...

Take a tea break and ponder on whether this is worth while..... of course it is - you're a man, man up....
My pondering took me to a time when I owned an MX-5 and I thought.. the BOSE on the cheap mazda didn't rattle......

Open the roof half way, remove cheeky rivets - there's one hidden at each end too.

Remove remaining top bolts and you'll find the whole trim panel starts to wiggle free - its held in around the centre console and removing this was a faff, you have to peel back the side covers slightly and work it free - a 2nd pair of hands or even a 3rd would have been a bonus but I managed to do it - you have to be weary as the plastic going into the centre console is dead sharp and will mark the soft leather arm rest...

Subs! Unbolt, unclip and take inside.....

4 screws hold in the sub, once removed it took a fair bit of prising to get it out but with care and force (forceful care?) out it will come.

Now go to town with the Dynamat, I coated the inside of the box, the back of the box, inside the metal enclosure on the car and parts of the bulkhead trim before slinging it all back together.

Now play some dance music with the BASS up and hope you haven't caused any new rattles in doing all this.

I lost a couple of rivets putting it back together so some spares would come in handy........

Ah I emailed them BSW to see if any of the speakers which are similar in parts used on the X3s I believe would fit, they replied saying the ones they offer are too deep - sad times.

So this was the next best option. I also snuck some Dynamat in behind the rear speakers which can't hurt. Not sure I can be bothered but I do have enough to do behind the door cards but I remember it being a total faff doing the doors on the E85.

Might do the centre speaker as that takes 5 seconds to pop out. Now to cure the dashboard rattle (passenger seat) grrrr

Billy has not logged in since August 2016. No one seems to be repairing this. In the interest of keeping E89 Z4 information available to all of us (information is scant for us Z4 owners), I have replicated the thread and images here: https://bmw.spoolstreet.com/threads/sou ... post-49047. I have this content as it was invaluable for the complete stereo change we did on my Z4. I've documented this on Spoolstreet where a number of E89 Z4 enthusiasts have been gathering.